4 This file is part of avahi.
6 avahi is free software; you can redistribute it and/or modify it
7 under the terms of the GNU Lesser General Public License as
8 published by the Free Software Foundation; either version 2.1 of the
9 License, or (at your option) any later version.
11 avahi is distributed in the hope that it will be useful, but WITHOUT
12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
13 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
14 Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with avahi; if not, write to the Free Software
18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
31 #include <avahi-common/malloc.h>
32 #include <avahi-common/error.h>
39 #include "wide-area.h"
41 #define MAX_CACHE_ENTRIES 500
43 typedef struct AvahiWideAreaCacheEntry AvahiWideAreaCacheEntry;
45 struct AvahiWideAreaCacheEntry {
46 AvahiWideAreaLookupEngine *engine;
49 struct timeval timestamp;
50 struct timeval expiry;
52 AvahiTimeEvent *time_event;
54 AVAHI_LLIST_FIELDS(AvahiWideAreaCacheEntry, by_key);
55 AVAHI_LLIST_FIELDS(AvahiWideAreaCacheEntry, cache);
58 struct AvahiWideAreaLookup {
59 AvahiWideAreaLookupEngine *engine;
62 uint32_t id; /* effectively just an uint16_t, but we need it as an index for a hash table */
63 AvahiTimeEvent *time_event;
65 AvahiKey *key, *cname_key;
68 AvahiDnsPacket *packet;
70 AvahiWideAreaLookupCallback callback;
73 AvahiAddress dns_server_used;
75 AVAHI_LLIST_FIELDS(AvahiWideAreaLookup, lookups);
76 AVAHI_LLIST_FIELDS(AvahiWideAreaLookup, by_key);
79 struct AvahiWideAreaLookupEngine {
83 AvahiWatch *watch_ipv4, *watch_ipv6;
88 AVAHI_LLIST_HEAD(AvahiWideAreaCacheEntry, cache);
89 AvahiHashmap *cache_by_key;
90 unsigned cache_n_entries;
93 AVAHI_LLIST_HEAD(AvahiWideAreaLookup, lookups);
94 AvahiHashmap *lookups_by_id;
95 AvahiHashmap *lookups_by_key;
99 AvahiAddress dns_servers[AVAHI_MAX_WIDE_AREA_SERVERS];
100 unsigned n_dns_servers;
101 unsigned current_dns_server;
104 static AvahiWideAreaLookup* find_lookup(AvahiWideAreaLookupEngine *e, uint16_t id) {
105 AvahiWideAreaLookup *l;
110 if (!(l = avahi_hashmap_lookup(e->lookups_by_id, &i)))
121 static int send_to_dns_server(AvahiWideAreaLookupEngine *e, AvahiDnsPacket *p) {
127 if (e->n_dns_servers <= 0)
130 assert(e->current_dns_server < e->n_dns_servers);
132 a = &e->dns_servers[e->current_dns_server];
134 if (a->proto == AVAHI_PROTO_INET) {
139 return avahi_send_dns_packet_ipv4(e->fd_ipv4, AVAHI_IF_UNSPEC, p, &a->data.ipv4, AVAHI_DNS_PORT);
142 assert(a->proto == AVAHI_PROTO_INET6);
147 return avahi_send_dns_packet_ipv6(e->fd_ipv6, AVAHI_IF_UNSPEC, p, &a->data.ipv6, AVAHI_DNS_PORT);
151 static void next_dns_server(AvahiWideAreaLookupEngine *e) {
154 e->current_dns_server++;
156 if (e->current_dns_server >= e->n_dns_servers)
157 e->current_dns_server = 0;
160 static void sender_timeout_callback(AvahiTimeEvent *e, void *userdata) {
161 AvahiWideAreaLookup *l = userdata;
166 /* Try another DNS server after three retries */
167 if (l->n_send >= 3 && avahi_address_cmp(&l->engine->dns_servers[l->engine->current_dns_server], &l->dns_server_used) == 0) {
168 next_dns_server(l->engine);
170 if (avahi_address_cmp(&l->engine->dns_servers[l->engine->current_dns_server], &l->dns_server_used) == 0)
171 /* There is no other DNS server, fail */
175 if (l->n_send >= 6) {
176 avahi_log_warn(__FILE__": Query timed out.");
177 avahi_server_set_errno(l->engine->server, AVAHI_ERR_TIMEOUT);
178 l->callback(l->engine, AVAHI_BROWSER_FAILURE, AVAHI_LOOKUP_RESULT_WIDE_AREA, NULL, l->userdata);
179 avahi_wide_area_lookup_free(l);
184 send_to_dns_server(l->engine, l->packet);
187 avahi_time_event_update(e, avahi_elapse_time(&tv, 1000, 0));
190 AvahiWideAreaLookup *avahi_wide_area_lookup_new(
191 AvahiWideAreaLookupEngine *e,
193 AvahiWideAreaLookupCallback callback,
197 AvahiWideAreaLookup *l, *t;
205 l = avahi_new(AvahiWideAreaLookup, 1);
208 l->key = avahi_key_ref(key);
209 l->cname_key = avahi_key_new_cname(l->key);
210 l->callback = callback;
211 l->userdata = userdata;
213 /* If more than 65K wide area quries are issued simultaneously,
214 * this will break. This should be limited by some higher level */
216 for (;; e->next_id++)
217 if (!find_lookup(e, e->next_id))
218 break; /* This ID is not yet used. */
220 l->id = e->next_id++;
222 /* We keep the packet around in case we need to repeat our query */
223 l->packet = avahi_dns_packet_new(0);
225 avahi_dns_packet_set_field(l->packet, AVAHI_DNS_FIELD_ID, (uint16_t) l->id);
226 avahi_dns_packet_set_field(l->packet, AVAHI_DNS_FIELD_FLAGS, AVAHI_DNS_FLAGS(0, 0, 0, 0, 1, 0, 0, 0, 0, 0));
228 p = avahi_dns_packet_append_key(l->packet, key, 0);
231 avahi_dns_packet_set_field(l->packet, AVAHI_DNS_FIELD_QDCOUNT, 1);
233 if (send_to_dns_server(e, l->packet) < 0) {
234 avahi_log_error(__FILE__": Failed to send packet.");
235 avahi_dns_packet_free(l->packet);
236 avahi_key_unref(l->key);
238 avahi_key_unref(l->cname_key);
245 l->time_event = avahi_time_event_new(e->server->time_event_queue, avahi_elapse_time(&tv, 500, 0), sender_timeout_callback, l);
247 avahi_hashmap_insert(e->lookups_by_id, &l->id, l);
249 t = avahi_hashmap_lookup(e->lookups_by_key, l->key);
250 AVAHI_LLIST_PREPEND(AvahiWideAreaLookup, by_key, t, l);
251 avahi_hashmap_replace(e->lookups_by_key, avahi_key_ref(l->key), t);
253 AVAHI_LLIST_PREPEND(AvahiWideAreaLookup, lookups, e->lookups, l);
258 static void lookup_stop(AvahiWideAreaLookup *l) {
264 avahi_time_event_free(l->time_event);
265 l->time_event = NULL;
269 static void lookup_destroy(AvahiWideAreaLookup *l) {
270 AvahiWideAreaLookup *t;
275 t = avahi_hashmap_lookup(l->engine->lookups_by_key, l->key);
276 AVAHI_LLIST_REMOVE(AvahiWideAreaLookup, by_key, t, l);
278 avahi_hashmap_replace(l->engine->lookups_by_key, avahi_key_ref(l->key), t);
280 avahi_hashmap_remove(l->engine->lookups_by_key, l->key);
282 AVAHI_LLIST_REMOVE(AvahiWideAreaLookup, lookups, l->engine->lookups, l);
284 avahi_hashmap_remove(l->engine->lookups_by_id, &l->id);
285 avahi_dns_packet_free(l->packet);
288 avahi_key_unref(l->key);
291 avahi_key_unref(l->cname_key);
296 void avahi_wide_area_lookup_free(AvahiWideAreaLookup *l) {
303 l->engine->cleanup_dead = 1;
307 void avahi_wide_area_cleanup(AvahiWideAreaLookupEngine *e) {
308 AvahiWideAreaLookup *l, *n;
311 while (e->cleanup_dead) {
314 for (l = e->lookups; l; l = n) {
323 static void cache_entry_free(AvahiWideAreaCacheEntry *c) {
324 AvahiWideAreaCacheEntry *t;
328 avahi_time_event_free(c->time_event);
330 AVAHI_LLIST_REMOVE(AvahiWideAreaCacheEntry, cache, c->engine->cache, c);
332 t = avahi_hashmap_lookup(c->engine->cache_by_key, c->record->key);
333 AVAHI_LLIST_REMOVE(AvahiWideAreaCacheEntry, by_key, t, c);
335 avahi_hashmap_replace(c->engine->cache_by_key, avahi_key_ref(c->record->key), t);
337 avahi_hashmap_remove(c->engine->cache_by_key, c->record->key);
339 c->engine->cache_n_entries --;
341 avahi_record_unref(c->record);
345 static void expiry_event(AvahiTimeEvent *te, void *userdata) {
346 AvahiWideAreaCacheEntry *e = userdata;
354 static AvahiWideAreaCacheEntry* find_record_in_cache(AvahiWideAreaLookupEngine *e, AvahiRecord *r) {
355 AvahiWideAreaCacheEntry *c;
360 for (c = avahi_hashmap_lookup(e->cache_by_key, r->key); c; c = c->by_key_next)
361 if (avahi_record_equal_no_ttl(r, c->record))
367 static void run_callbacks(AvahiWideAreaLookupEngine *e, AvahiRecord *r) {
368 AvahiWideAreaLookup *l;
373 for (l = avahi_hashmap_lookup(e->lookups_by_key, r->key); l; l = l->by_key_next) {
374 if (l->dead || !l->callback)
377 l->callback(e, AVAHI_BROWSER_NEW, AVAHI_LOOKUP_RESULT_WIDE_AREA, r, l->userdata);
380 if (r->key->clazz == AVAHI_DNS_CLASS_IN && r->key->type == AVAHI_DNS_TYPE_CNAME) {
381 /* It's a CNAME record, so we have to scan the all lookups to see if one matches */
383 for (l = e->lookups; l; l = l->lookups_next) {
386 if (l->dead || !l->callback)
389 if ((key = avahi_key_new_cname(l->key))) {
390 if (avahi_key_equal(r->key, key))
391 l->callback(e, AVAHI_BROWSER_NEW, AVAHI_LOOKUP_RESULT_WIDE_AREA, r, l->userdata);
393 avahi_key_unref(key);
399 static void add_to_cache(AvahiWideAreaLookupEngine *e, AvahiRecord *r) {
400 AvahiWideAreaCacheEntry *c;
406 if ((c = find_record_in_cache(e, r))) {
409 /* Update the existing entry */
410 avahi_record_unref(c->record);
412 AvahiWideAreaCacheEntry *t;
416 /* Enforce cache size */
417 if (e->cache_n_entries >= MAX_CACHE_ENTRIES)
418 /* Eventually we should improve the caching algorithm here */
421 c = avahi_new(AvahiWideAreaCacheEntry, 1);
423 c->time_event = NULL;
425 AVAHI_LLIST_PREPEND(AvahiWideAreaCacheEntry, cache, e->cache, c);
427 /* Add the new entry to the cache entry hash table */
428 t = avahi_hashmap_lookup(e->cache_by_key, r->key);
429 AVAHI_LLIST_PREPEND(AvahiWideAreaCacheEntry, by_key, t, c);
430 avahi_hashmap_replace(e->cache_by_key, avahi_key_ref(r->key), t);
432 e->cache_n_entries ++;
435 c->record = avahi_record_ref(r);
437 gettimeofday(&c->timestamp, NULL);
438 c->expiry = c->timestamp;
439 avahi_timeval_add(&c->expiry, r->ttl * 1000000);
442 avahi_time_event_update(c->time_event, &c->expiry);
444 c->time_event = avahi_time_event_new(e->server->time_event_queue, &c->expiry, expiry_event, c);
452 static int map_dns_error(uint16_t error) {
453 static const int table[16] = {
455 AVAHI_ERR_DNS_FORMERR,
456 AVAHI_ERR_DNS_SERVFAIL,
457 AVAHI_ERR_DNS_NXDOMAIN,
458 AVAHI_ERR_DNS_NOTIMP,
459 AVAHI_ERR_DNS_REFUSED,
460 AVAHI_ERR_DNS_YXDOMAIN,
461 AVAHI_ERR_DNS_YXRRSET,
462 AVAHI_ERR_DNS_NXRRSET,
463 AVAHI_ERR_DNS_NOTAUTH,
464 AVAHI_ERR_DNS_NOTZONE,
465 AVAHI_ERR_INVALID_DNS_ERROR,
466 AVAHI_ERR_INVALID_DNS_ERROR,
467 AVAHI_ERR_INVALID_DNS_ERROR,
468 AVAHI_ERR_INVALID_DNS_ERROR,
469 AVAHI_ERR_INVALID_DNS_ERROR
477 static void handle_packet(AvahiWideAreaLookupEngine *e, AvahiDnsPacket *p, AvahiAddress *a) {
478 AvahiWideAreaLookup *l = NULL;
481 AvahiBrowserEvent final_event = AVAHI_BROWSER_ALL_FOR_NOW;
486 /* Some superficial validity tests */
487 if (avahi_dns_packet_check_valid(p) < 0 || avahi_dns_packet_is_query(p)) {
488 avahi_log_warn(__FILE__": Ignoring invalid response for wide area datagram.");
492 /* Look for the lookup that issued this query */
493 if (!(l = find_lookup(e, avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ID))) || l->dead)
496 /* Check whether this a packet indicating a failure */
497 if ((r = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) & 15) != 0 ||
498 avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ANCOUNT) == 0) {
500 avahi_server_set_errno(e->server, r == 0 ? AVAHI_ERR_NOT_FOUND : map_dns_error(r));
501 /* Tell the user about the failure */
502 final_event = AVAHI_BROWSER_FAILURE;
504 /* We go on here, since some of the records contained in the
505 reply might be interesting in some way */
508 /* Skip over the question */
509 for (i = (int) avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_QDCOUNT); i > 0; i--) {
512 if (!(k = avahi_dns_packet_consume_key(p, NULL))) {
513 avahi_log_warn(__FILE__": Wide area response packet too short.");
514 avahi_server_set_errno(e->server, AVAHI_ERR_INVALID_PACKET);
515 final_event = AVAHI_BROWSER_FAILURE;
522 /* Process responses */
523 for (i = (int) avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ANCOUNT) +
524 (int) avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_NSCOUNT) +
525 (int) avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ARCOUNT); i > 0; i--) {
529 if (!(rr = avahi_dns_packet_consume_record(p, NULL))) {
530 avahi_log_warn(__FILE__": Wide area response packet too short (2).");
531 avahi_server_set_errno(e->server, AVAHI_ERR_INVALID_PACKET);
532 final_event = AVAHI_BROWSER_FAILURE;
537 avahi_record_unref(rr);
544 l->callback(e, final_event, AVAHI_LOOKUP_RESULT_WIDE_AREA, NULL, l->userdata);
550 static void socket_event(AvahiWatch *w, int fd, AvahiWatchEvent events, void *userdata) {
551 AvahiWideAreaLookupEngine *e = userdata;
553 AvahiDnsPacket *p = NULL;
555 if (fd == e->fd_ipv4) {
556 struct sockaddr_in sa;
558 if ((p = avahi_recv_dns_packet_ipv4(e->fd_ipv4, &sa, NULL, NULL, NULL)))
559 avahi_address_from_sockaddr((struct sockaddr*) &sa, &a);
561 } else if (fd == e->fd_ipv6) {
562 struct sockaddr_in6 sa6;
564 if ((p = avahi_recv_dns_packet_ipv6(e->fd_ipv6, &sa6, NULL, NULL, NULL)))
565 avahi_address_from_sockaddr((struct sockaddr*) &sa6, &a);
570 handle_packet(e, p, &a);
571 avahi_dns_packet_free(p);
575 AvahiWideAreaLookupEngine *avahi_wide_area_engine_new(AvahiServer *s) {
576 AvahiWideAreaLookupEngine *e;
580 e = avahi_new(AvahiWideAreaLookupEngine, 1);
585 e->fd_ipv4 = avahi_open_unicast_socket_ipv4();
586 e->fd_ipv6 = avahi_open_unicast_socket_ipv6();
588 if (e->fd_ipv4 < 0 && e->fd_ipv6 < 0) {
589 avahi_log_error(__FILE__": Failed to create wide area sockets: %s", strerror(errno));
603 e->watch_ipv4 = s->poll_api->watch_new(e->server->poll_api, e->fd_ipv4, AVAHI_WATCH_IN, socket_event, e);
605 e->watch_ipv6 = s->poll_api->watch_new(e->server->poll_api, e->fd_ipv6, AVAHI_WATCH_IN, socket_event, e);
607 e->n_dns_servers = e->current_dns_server = 0;
608 e->next_id = (uint16_t) rand();
610 /* Initialize cache */
611 AVAHI_LLIST_HEAD_INIT(AvahiWideAreaCacheEntry, e->cache);
612 e->cache_by_key = avahi_hashmap_new((AvahiHashFunc) avahi_key_hash, (AvahiEqualFunc) avahi_key_equal, (AvahiFreeFunc) avahi_key_unref, NULL);
613 e->cache_n_entries = 0;
615 /* Initialize lookup list */
616 e->lookups_by_id = avahi_hashmap_new((AvahiHashFunc) avahi_int_hash, (AvahiEqualFunc) avahi_int_equal, NULL, NULL);
617 e->lookups_by_key = avahi_hashmap_new((AvahiHashFunc) avahi_key_hash, (AvahiEqualFunc) avahi_key_equal, (AvahiFreeFunc) avahi_key_unref, NULL);
618 AVAHI_LLIST_HEAD_INIT(AvahiWideAreaLookup, e->lookups);
623 void avahi_wide_area_engine_free(AvahiWideAreaLookupEngine *e) {
626 avahi_wide_area_clear_cache(e);
629 lookup_destroy(e->lookups);
631 avahi_hashmap_free(e->cache_by_key);
632 avahi_hashmap_free(e->lookups_by_id);
633 avahi_hashmap_free(e->lookups_by_key);
636 e->server->poll_api->watch_free(e->watch_ipv4);
639 e->server->poll_api->watch_free(e->watch_ipv6);
650 void avahi_wide_area_clear_cache(AvahiWideAreaLookupEngine *e) {
654 cache_entry_free(e->cache);
656 assert(e->cache_n_entries == 0);
660 void avahi_wide_area_set_servers(AvahiWideAreaLookupEngine *e, const AvahiAddress *a, unsigned n) {
665 for (e->n_dns_servers = 0; n > 0 && e->n_dns_servers < AVAHI_MAX_WIDE_AREA_SERVERS; a++, n--)
666 if ((a->proto == AVAHI_PROTO_INET && e->fd_ipv4 >= 0) || (a->proto == AVAHI_PROTO_INET6 && e->fd_ipv6 >= 0))
667 e->dns_servers[e->n_dns_servers++] = *a;
670 e->n_dns_servers = 0;
673 e->current_dns_server = 0;
675 avahi_wide_area_clear_cache(e);
678 void avahi_wide_area_cache_dump(AvahiWideAreaLookupEngine *e, AvahiDumpCallback callback, void* userdata) {
679 AvahiWideAreaCacheEntry *c;
684 callback(";; WIDE AREA CACHE ;;; ", userdata);
686 for (c = e->cache; c; c = c->cache_next) {
687 char *t = avahi_record_to_string(c->record);
688 callback(t, userdata);
693 unsigned avahi_wide_area_scan_cache(AvahiWideAreaLookupEngine *e, AvahiKey *key, AvahiWideAreaLookupCallback callback, void *userdata) {
694 AvahiWideAreaCacheEntry *c;
702 for (c = avahi_hashmap_lookup(e->cache_by_key, key); c; c = c->by_key_next) {
703 callback(e, AVAHI_BROWSER_NEW, AVAHI_LOOKUP_RESULT_WIDE_AREA|AVAHI_LOOKUP_RESULT_CACHED, c->record, userdata);
707 if ((cname_key = avahi_key_new_cname(key))) {
709 for (c = avahi_hashmap_lookup(e->cache_by_key, cname_key); c; c = c->by_key_next) {
710 callback(e, AVAHI_BROWSER_NEW, AVAHI_LOOKUP_RESULT_WIDE_AREA|AVAHI_LOOKUP_RESULT_CACHED, c->record, userdata);
714 avahi_key_unref(cname_key);
720 int avahi_wide_area_has_servers(AvahiWideAreaLookupEngine *e) {
723 return e->n_dns_servers > 0;